Brake apparatus for wheels



- Aug. 25,1936. s. SAITO ET AL BRAKE APPARATUS FOR WHEELS' Original Filed'Aug. 4, 1934 Patented Aug. 25, 1936 PATENT OFFICE 2,051,968 BRAKE APPARATUS FOR WHEELS Seizo Saito, Toyonaka-cho, and Nobutaka Yamamoto, Osaka, Japan Original application August 4, 1934, Serial No. 738,512. Divided and this application July 15,

1935, Serial No.

2 Claims.

This invention relates to a brake apparatus for a wheel consisting of one or more brakeshoes made of steel accompanied by a means which may press the shoes to the wheel in use, and one or more contact pieces made of a solid organic substance, which may not serve as a lubricant per se, accompanied by a means which may lightly maintain the pieces in contact with .the wheel continuously or intermittently.

The Patent No. 1,979,906 describes that the abrasion of brake shoes is far lessened incase where a pair of brake shoes made respectively of different materials are used for a wheel compared with the case where a pair of brake shoes of the same material are used. Now it has been found that the abrasion of brake shoes. and wheels can be lessened when one or more brake shoes made of steel and a contact piece or pieces, which does not act as a brake shoe or shoes, made of a solid organic substance are. employed for a wheel, the piece or pieces being lightly maintained in contact continuously or intermittently with the wheel. The theory of this phenomenon is not fully clear, but the eil'ect is, and can be, proved by experiments.

This invention is based upon the above mentioned investigation. According to this invention, brake shoe or shoes made of steel, either carbon steel or alloy steel, are used so as to be pressed to a wheel as usuaL-and a contact piece or pieces are maintained on the wheel in such a manner that they are lightly pressed to the wheel continuously or intermittently, by means of a pressure-exerting device such as springs, weights, etc. The contact piece should be made of a solid organic substance, which may not serve as a lubricant per se, for example, wood, hard rubber, resinous compounds, fibrous materials and bituminous materials.

The accompanying drawing shows three examples of the brake apparatus according to this invention.

Fig. 1 is a diagrammatical elevation of a wheel with steel shoes and a wood contact piece which is continuously in contact with the wheel. Figs. 2 and 3 are similar views wherein a contact piece is intermittently in contact with the wheel. In the drawing the same reference number indicates the same or similar part.

In Figs. 1 to 3, A is a brake shoe made of steel which is operated in the known manner when the wheel is braked, and B is a contact piece made of wood.

The contact piece is slidably fitted to a guide cylinder i which is held on the axle box of the wheel, not shown. I

2 is a spring mounted on the contact piece provided in the guide cylinder, which always presses the contact piece on the tire of the wheel.

3 is an electric magnet provided in the guide cylinder, which pulls the contact piece while electric current is passing in the coil, so that the piece is kept from contact with the wheel.

4 is an air cylinder the piston therein being connected with the contact piece provided in the guide cylinder. In this manner the contact piece is controlled in its contact with the wheel by compressed air which is manually admitted from its source.

According to the devices shown in Figs. 2 and 3, the contact piece can be simultaneously put in contact with the wheel in case electric current for main motors of the car is cut off or compressed air is admitted to the brake apparatus.

Lubricating material such as graphite is generally applied to a sliding surface in order to avoid the abrasion of the material, but such a lubricating material cannot be applied to the surface of a, brake shoe, because the coeificient 20 of friction at the surface is decreased so that a sufficient braking efiect cannot be obtained.

In this invention, however, a material which may not serve as a lubricantper se is applied to the surface of the wheel, therefore the coeificient of friction is in no way decreased giving any influence to the braking effect but greatly lessening the abrasion of the brake shoes and wheel.

The same result can be obtained when brake -shoes made of malleable cast iron are used instead of steel shoes, because malleable cast iron has similar properties to those of steel.

The drawing only shows some typical examples of this invention, and several other modifications can be carried out according to the principle of this invention, so that this invention is not limited to these examples.

Whatwe claim is:

1. A. brake apparatus for a wheel, comprising a brake shoe made of material selected from the group consisting of steel and malleable cast iron, a contact piece made of a substance selected from the group consisting of wood, bituminous material, resinous material, fibrous material, and hard rubber, and means for maintaining said contact piece lightly incontact with the wheel, to prevent excessive wear of said brake shoe.

2. A brake apparatus for a wheel, comprising a brake shoe made of material selected from the group consisting of steel and malleable cast' 

